README

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   :alt: pybind11 logo

pybind11 (v3)  — Seamless interoperability between C++ and Python

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Setuptools example _
• Scikit-build example _
• CMake example _

.. start


pybind11 is a lightweight header-only library that exposes C++ types
in Python and vice versa, mainly to create Python bindings of existing
C++ code. Its goals and syntax are similar to the excellent
Boost.Python _
library by David Abrahams: to minimize boilerplate code in traditional
extension modules by inferring type information using compile-time
introspection.

The main issue with Boost.Python—and the reason for creating such a
similar project—is Boost. Boost is an enormously large and complex suite
of utility libraries that works with almost every C++ compiler in
existence. This compatibility has its cost: arcane template tricks and
workarounds are necessary to support the oldest and buggiest of compiler
specimens. Now that C++11-compatible compilers are widely available,
this heavy machinery has become an excessively large and unnecessary
dependency.

Think of this library as a tiny self-contained version of Boost.Python
with everything stripped away that isn't relevant for binding
generation. Without comments, the core header files only require ~4K
lines of code and depend on Python (CPython 3.9+, PyPy, or GraalPy) and the C++
standard library. This compact implementation was possible thanks to some C++11
language features (specifically: tuples, lambda functions and variadic
templates). Since its creation, this library has grown beyond Boost.Python in
many ways, leading to dramatically simpler binding code in many common
situations.

Tutorial and reference documentation is provided at
pybind11.readthedocs.io _.
A PDF version of the manual is available
here _.
And the source code is always available at
github.com/pybind/pybind11 _.


Core features
-------------


pybind11 can map the following core C++ features to Python:

- Functions accepting and returning custom data structures per value,
  reference, or pointer
- Instance methods and static methods
- Overloaded functions
- Instance attributes and static attributes
- Arbitrary exception types
- Enumerations
- Callbacks
- Iterators and ranges
- Custom operators
- Single and multiple inheritance
- STL data structures
- Smart pointers with reference counting like std::shared_ptr
- Internal references with correct reference counting
- C++ classes with virtual (and pure virtual) methods can be extended
  in Python
- Integrated NumPy support (NumPy 2 requires pybind11 2.12+)

Goodies
-------

In addition to the core functionality, pybind11 provides some extra
goodies:

- CPython 3.9+, PyPy3 7.3.17+, and GraalPy 24.1+ are supported w